In recent years, there has been a demand for preparation of a toner having a small particle size and a sharp particle size distribution, from the viewpoint of formation of higher image qualities and the like. However, the smaller the particle size of the toner, the more likely the generation of aggregation between the particles, thereby making it difficult to classify the particles.
As for classifiers, besides generally conventionally used jet stream type classifiers, a classifier having a classifying rotor has been reported (see JP-A-Hei-11-216425 and JP2004-78063 A).
On the other hand, in the preparation of a toner containing a wax, a technique including the steps of mixing roughly pulverized products with fine inorganic oxide particles, and thereafter further pulverizing the mixture, has been reported (see JP-A-Hei-11-202551).
In addition, the more the intention of obtaining a toner having a smaller particle size, the more likely the generation of fine powders.
As a pulverizer, a fluidized bed type jet mill has been known as a pulverizer having high efficiency in pulverization (see JP-A-Showa-60-168547 and JP2002-35631 A). However, the smaller the particle size of the powder, the more likely the powders are aggregated, so that the fluidity is likely to be lowered. Therefore, the aggregated products may be deposited to or solidly fused on the inner wall of the pulverizer in some cases. In view of the above, a pulverizer provided with a layer made of a releasing agent on the side of the inner wall of the fluidized tank has been proposed (see JP2003-280263 A).
On the other hand, in the preparation of a toner containing a wax, a technique including the steps of mixing roughly pulverized products with fine inorganic oxide particles, and thereafter further pulverizing the mixture, has been reported (see JP-A-Hei-11-202551).